socaltek,
While I cannot speak for your specific situation, I have noticed that in the last month or so two of my email addresses are getting spammed everyday with about 10 messages each. This is with the two United Online email systems, Juno and Netzero. This has happened before and it continues for maybe a couple of months or so or maybe a little longer. But then it abruptly stops---until the next time. Next time could be 6 months later, a year, or even longer. But there usually is an intense cycle and then it stops. I report all of these to the spam folder and I will say that Juno and Netzero are fairly good with filtering out most spam. But somehow these get through.
I have NOT changed my email addresses because of this for like yourself I have had them for a long time. At the present moment there may not be a universal fix for this kind of spam. Given the patterns that I have seen there are too many ways that an email address could be found, if not by breaking into someone's email address book or history (not necessarily yours but perhaps those of some correspondents) or by simply using computer-generated name possibilities for all email services, etc.
While I find it a nuisance, at this volume it is not crippling. Now maybe if there were 50-100 everyday I would have to take other actions. But from 10-30 or so I have not found it to be a significant problem. The spams are easily recognizable and they are usually clustered together or contiguous so reporting them to the spam folder is not that time-consuming.
All in all I have just accepted this as part of the environment for using email, just like traffic is a part of driving and junk mail is a part of the postal mail system.
So no good news, just another experience to add to the pot!